Hi Folks,
I have been asked to take a look at this Luego which has a running problem, its fitted with a Zetec 2ltr with Fenspeed throttle bodies and a stand alone ECU, its sounds like its misfiring throughout the rev range and the following have been replaced/checked by another mechanic. PLUGS/COILPACK/.VACUUM PIPES/INTAKE RUBBERS/PLUG LEADS/FUEL PRESSURE. it doesn't seem to run on number 4 cyl at low revs and pops through the exhaust on the overrun.I can see fuel being squirted in from the injector. I have compression checked it and all cylinders are even and high. ive used carb cleaner sprayed into the intake of number 4 cyl, this does nothing and check for air leaks non found. I have found that the cam position sensor is not used? and apparently never has been?. there is a Lamba sensor which makes no difference when disconnected. as its using Throttle bodies it doesn't use a Mass airflow meter. I have checked to see if the timing is advancing at revs and it only advances very slightly ,so I think it may be a problem within the ECU, there is no name on this ECU it does have a small vacuum pipe going to it which has good vacuum, and it does actually run better with this pipe blocked.

I wondered if anyone knows this car or who built it as they may be able to shed light on any problems they had with it, as the current owner knows absolutely nothing about cars and has spent a fortune with other garages trying to sort it out.

Thanks for any info

Alfie

[Edited on 9/7/19 by alfiebeard]

Might be worth doing a cylinder leakage test, I once had problems with a Escort with a Zetec that had a lumpy idle, even passed an MOT test like it . Compressions were good and even but a leakage test showed valve problems. If no air leaks try swapping no 4 injector with one from another cylinder? By the sound of it the engine has either individual throttle bodies or carbs? Check the balance?

Hi cheers for the reply,

I did actually swop round the injectors but the fault remained, I did do a compression test which was bang on. but I will do a leakage test and see what it shows up.

Kind Regards

Alfie

How have you traced in to No 4 cylinder have you popped a plug lead off or something else?

I was initially going to suggest it might be the Crank sensor or TPS until you mentioned the issue just on No 4

Tried swapping the plug lead aswell as the injector?

Is the engine a black top or silver top? Black top use shims to adjust the valve clearances , could be tight valve(s) which would cause your symptoms. Silver top engines use hydraulic tappets which can cause problems especially if the correct 5/30 oil isn’t used . Might also be worth checking the injector is actually firing by using a noir light or oscilloscope. Have you checked the balance of the TBs? If no 4 isn’t open at all it will not run on that cylinder

I would check the plug gaps and that the throttle bodies are well balanced.

A picture of the ECU might help somebody recognise it, it's possibly a Megasquirt they were unbranded & relied on a sticker being put on.

Hi Folks,
Thanks very much for all your replies it did turn out to be the throttle bodies were miles out, I used my trusty old Hometune vacuum balancer and it showed that number 4 was very late in opening. after I had balanced them it ran a 100% better although not very even on tickover but the owner can fiddle about to get that better.

The owner says he's happy with it so sod it he can have it back. thanks again chaps you've been a great help.

Alfie

[Edited on 11/7/19 by alfiebeard]